National Ambulatory Medical Care Survey, Public-use file, 1973-2016

The National Ambulatory Medical Care Survey (NAMCS) is a national survey designed to meet the need for objective, reliable information about the provision and use of ambulatory medical care services in the United States. Findings are based on a sample of visits to non-federally employed office-based physicians who are primarily engaged in direct patient care. Physicians in the specialties (including designated sub-specialties) of anesthesiology, pathology, and radiology are excluded from the survey. The survey was conducted annually from 1973 to 1981, again in 1985, and annually since 1989. Data collection from the physician, rather than from the patient, provides an analytic base that expands information on ambulatory care collected through other NCHS surveys. Data about the physician and their practice characteristics are collected during a survey induction interview. For survey years 1973 to 1991, there are two data files: one for patient visit data and a second for drug mention data. The second file is limited to those visits with mention of medication therapy. For the 1991 data, it is possible to link information on the drug file with information on the patient visit file. Beginning with the 1992 survey year through 2011, one main data file was produced annually that contains both patient visit and drug information.